Metal furniture



0st. 8, 1946. E. c. BOOTH METAL FURNITURE 2 Sheets-Sheet 1 Filed Aug.31, 1944 I v I INVENTOR.

.549 0. Boom,

Oct. 8, 1946. E. c. BOOTH METAL FURNITURE 2 Sheets'Sheet 2 Filed Aug.31, 1944 INVENTOR. [n24 Cfiaar; I

Patented Oct. 8, 1946 METAL FURNITURE Earl C. Booth, Columbus, Ind,assignor to Noblitt- Sparks Industries, Inc., Columbus, Ind., acorporation of Indiana Application August 31, 1944, Serial No. 552,141

9 Claims.

My invention relates to a joint structurefor structural metal tubing,and has for its object the provision of a joint structure by which twometal tubes may b removably connected together in a manner which willprovide adequately for the transmission of stresses from one tube to theother. A further object of I my invention is to produce a jointstructure which will be sightly in appearance and which will not involveexpensive manufacturin operations,

In carrying out my invention, I collapse for a portion of its length oneof the tubes which are to be joined together, and I so shape thecollapsed portion of the tube that it will fit against the exteriorsurface of the other tube. In the preferred form of construction, thecollapsed tubeportion is made arcuate in cross section with thecurvature of its outer surface conforming to the curvature of theuncollapsed tube-section, and that portion. of the other tube which isto receive the collapsed portion is displaced inwardly in such a mannerthat the outer surface of the collapsed tube-portion will be flush withthe outer surface of the other tube.

The accompanying drawings illustratemy invention: Fig. l is a plan Viewof one form of joint between the ends of two tubes wh ch lie perpenedicular to each other; Fig. 2 is an axial section through the joint ofFig. 1; Fig. 3 is a transverse section on the line S3 of Fig. 2; Fig. 4is a plan view of a modified form of joint useful where one tube isjoined to an intermediate point on the other Fig. 5 is a sectional viewillustrating a joint for use when the two joined tubes are not coplanar;Fig. dis a View similar to Fig. 1 illustrating a modified form of joint;Figs. '7 and 8 are end elevations of the two tubes which when unitedform the joint of Fig. 6; and Fig. 9 is a section on the line 99 of Fig.6.

The joint structure illustrated in Fig. 1 is one suitable for use wherethe ends of two tubes of the same diameter and lying perpendicularly toeach other are to be joined. One of the tubes, here shown as the tubeI0, is collapse, substantially completely, for a distance back from oneend. The collapsed portion of the tube, indicated by the referencenumeral II, is given an arcuate shape in cross-section and is bentperpendicularly to the body of the tube with the concave side of thearcuate cross-section on the inside of the bend. The change in thecross-sectional shape of the tube II] from the circular shape of thetube-body to the arcuate shape of the collapsed portion II is desirablynot an abrupt change, but instead the tube is formed so that the concaveinner surface 2 of the collapsed portion II merges with the uncollapsedbody of the tube through a groove '12 of gradually decreasing depth. Thecollapsed crosssection of the tube at the point where it is bent makespossible a bend of very short radius.

The inner surface of the collapsed portion I! of the tube I0 fitsagainst the outer surface of the other tube I4, and is securedthereagainst by a bolt l3. In the preferred structure, the engagingsurfaces of the tube l4 andof the collapsed portion II are so formedthat the outer surface of the collapsed portion will be flush with theouter surface of the body of the tube l4. To this end, that portion ofthe wall of the tube is which is to be engaged by the collapsed portionII is offset inwardly, as will be clear from Fig. 3. As shown, theinwardly offset portion of the tube i4 is provided in opposite sideswith indentations or grooves extending back for a distance from its endand providing two approximately parallel walls I5 and two axiallyextending shoulders Iii contiguous to such parallel wall-portions. Theexterior surface of the collapsed portion II of the tube Ill is shapedto conform to the curvature of the undistorted body of the tube M, whilethe inner surface of the collapsed portion 1 I is formed in a channelsection having side walls I! adapted to receive between them the twoparallel walls lb of the tube I4,

When the two tubes I0 and I l are placed together as shown in Figs. 1,2, and 3, the interengagement of the walls l5 and I? will serve to holdthe two tubes positively in coplanar relationship. When the bolt I3 istightened, the edges of the collapsed portion II will be drawn tightlyagainst the shoulders It, thus holding the two tubes in the properangular relationship to each other.

At their inner ends the shoulders I5 curve smoothly toward theundistorted portion of the tube I4, as indicated at I9, and the end ofthe collapsed portion I I of the tube I0 is trimmed to fit against thiscurved portion of the shoulder. The end of the tube I4 is desirablybeveled so that it does not interfere with the inner surface of the bendin the collapsed portion IE and so that its extreme tip will lie withinthe groove I2.

The joint shown in Figs. 1, 2, and 3 is strong and rigid against allpossible disturbing forces. The interengaging side walls l5 and Hprevent any rotation of the tube I4 about the axis of the tube I ll. Thebolt I3, by holding the edges of the collapsed portion I I against theelongated shoulders l6 prevents any relative angular displacement-of thetwo tubes in their common plane, and

also prevents rotation of the tube I4 about its own axis. At the sametime, the joint is attractive in appearance, as the outer surface of thecollapsed portion II is substantially a continuation of the outersurface of the tube I4 while the extreme end of the tube I4 isinconspicuously hidden within the groove l2.

The joint illustrated in Fig. 4 is one suitable for use where one tube,designated as 20, is to be secured in a perpendicular position againstthe side of another tube 22 at an intermediate point thereof. In thisconstruction, the tube 20 is provided with a collapsed end portion 2|similar to the collapsed portion ll of the tube l0, but the collapsedportion 2| is bent perpendicularly to the body of the tube so that itsinner surface as Well as the groove I2 through which such inner surfacemerges with the undistorted body of the tube 20 lies on the outside ofthe bend. Here again the collapsed cross-section of the tube makespossible a bend of very short radius. Desirably the collapsed portion 2|and that portion of the tube 22 which it engages are formed in crosssection like the interfitting portions of the tubes Ill and M in Figs. 1to 3. A bolt 24 extending diametrically through the tube 22 andcollapsed portion 2| serves to secure the two tubes together. Inrigidity and appearance, the joint of Fig. 4 possesses the sameadvantages as that of Figs. 1, 2, and 3.

The joint of Fig. may be employed at a point where the two tubes do notlie in a common plane. In the specific construction shown, one tube 25is collapsed, as at 26, for a portion of its length, an arcuatecross-sectional shape is imparted to the collapsed portion 26 as in thejoints previously described, and the inner surface of the collapsedportion merges with the outer surface of the undistorted tube throughgrooves 21 of gradually diminishing depth similar to the groove I2 inFigs. 1 to 4. The collapsed portion 26 of the tube 25 is bent so thatthe two undistorted sections of the tube lying beyond it will bedisposed perpendicularly to each other, the radius of the bend beingsuch that the edges of the collapsed portion 26 will fit against theouter surface of a second tube 28 disposed perpendicularly to the planeof the bent tube 25. Desirably, the edges of the collapsed portion 26embrace the tube 28 for substantially 180. A bolt 29 extending throughthe collapsed portion 26 and diametrically through the tube 28 serves tohold the two tubes together. The bolt 28 is preferably located in theplane bisecting the angle between the two undistorted portions of thetube 25.

The joint structure shown in Figs. 6 to 9 is a I substitute for thatshown in Figs. 1 to 3 in that it may be used for joining together theends of two tubes disposed at right-angles to each other. In the jointof Figs. 6 to 9 one of the tubes, shown as the tube 30, has a collapsedend portion 3| formed generally similarly to the collapsed portion ofthe tube in Fig. 4 and bent so that it lies perpendicularly to the axisof the tube 30 with the inner surface of the collapsed portion on theoutside of the bend. The other tube 32 has a collapsed end portion 33formed generally similarly to the collapsed portion H of the tube In inFigs. 1 to 3 and bent so that it extends perpendicularly to the tube 32with the inner surface of the collapsed portion on the inside of thebend. The two tubes 30 and 32 are put together in the manner illustratedin Fig. 6 with the collapsed portion of each engaging the outer surfaceof the other, and the two tubes tween the Walls 35.

are then secured together by bolts 34 each passing through a collapsedportion of one tube near one end thereof and through the other tube,such bolts lying in the common plane of the two tubes.

I have found that the rigidity provided by the joint of Fig. 6 can beincreased if the collapsed portions 3| and 33 are provided interiorlywith opposed surfaces 35 which approach parallelism and if thetube-section received within each collapsed portion is also providedwith approximately parallel walls adapted to be received be- Toaccomplish this result, each of the tubes 30 and 32 is flattened in thecommon plane of the tubes over that portion of its length in contactwith the collapsed portion of the other tube, such flattening providingtwo substantially parallel walls 35 spaced to be received between thesurfaces 35.

It is to be noted that in each of the structures described above thecollapsed tube-portion engages the other tube over surfaces which lie n,or which contain portions lying in, planes extending longitudinally ofone tube and substantially parallel to the bolt by which the tubes aresecured together. In such a construction, forces transmitted from onetube to the other through such surfaces have no substantial componentcapable of introducing tensile stresses in the bolt.

I claim as my invention:

1. In combination, a metal tube, the wall of said tube being indented onopposite sides of the tube to provide two generally parallel wallportions and shoulders contiguous thereto extending longitudinally ofthe tube, a second metal tube, said second tube being collapsed to bringtogether diametrically opposite parts of its wall and create adouble-layered portion, said doublelayered portion being curved incross-section with the curvature of the outer surface of the tube andthe curvature of the outer layer conforming substantially to thecurvature of the outer surface of the tube and with the inner layerformed to provide two opposed surfaces receiving between them thegenerally parallel walls of the first tube, the edges of the collapsedportion of the second tube being seated against the shoulders of thefirst tube, and a bolt extending transversely through both tubesgenerally parallel to said parallel walls.

2. In combination, a metal tube, the wall of said tube being indented onopposite sides of the tube to provide two generally parallel wallportions and shoulders contiguous thereto extending longitudinally ofthe tube, a second metal tube, said second tube being collapsed to bringtogether diametrically opposite parts of its wall and create adouble-layered portion, said doublelayered portion being curved incross-section with the curvature of the outer layer conformingsubstantially to the curvature of the outer surface of the tube and withthe inner layer formed to provide two opposed surfaces receiving betweenthem the generally parallel walls of the first tube, the edges of thecollapsed portion of the second tube being seated against the shouldersof the first tube, and means acting between said tubes for forcing theedges of the collapsed portion of the second tube into engagement withthe shoulders of the first tube.

3. In combination, a metal tube, the wall of said tube being offsetinwardly for a portion of the length and for a portion only of thecircumference of the tube to leave another portion of thetube-circumference undistorted, a second metal tube, said second tubebeing collapsed to bring together diametrically opposite parts of itswall and create a portion of double thickness, said collapsed portion ofthe second tube overlapping the offset portion of the first tube andbeing formed interiorly to fit against at least a portion of the outersurface of such ofiset portion, and means acting between said collapsedand offset portions for holding them together.

4. The invention set forth in claim 3 with the addition that saidcollapsed portion is curved in cross-section so that its outer face issubstantially flush with the outer surface of the undistorted portion ofsaid first tube.

5. In combination, a metal tube, the wall of said tube being indented onopposite sides of the tube to provide two shoulders extendinglongitudinally of the tube, a second metal tube, said second tube beingcollapsed to bring together diametrically opposite parts of its wall andcreate a double-layered portion, said double-layered portion beingcurved in cross-section, the edges of the collapsed portion of thesecond tube being seated against the shoulders of the first tube, andmeans acting between said tubes for forcing the edges of the collapsedportion of the second tube into engagement with the shoulders of thefirst tube.

6. In combination, a cylindrical metal tubular member collapsed over apart of its length to create a portion of double thickness, a secondcylindrical member, a, bolt extending through the double-thicknessportion and said second member for securing them together, saiddouble-thickness portion and second member being provided withinterengaging surfaces at least portions of which are disposed in planesextending longitudinally of the second member and lying on oppositesides of and substantially parallel to said bolt.

'1. The invention set forth in claim 6 with the addition that saiddouble-thickness portion is bent relative to the uncollapsed portion ofthe first named cylindrical member.

8. The invention set forth in claim 6 with the addition that both saidmembers lie in a common plane.

9. The invention set forth in claim 6 with the addition that saiddouble-thickness portion is arcuate in cross-section and engages saidsecond member near one end thereof, said double-thickness portion beingbent over the end of the second member.

EARL C. BOOTH.

